Cast cutter



' B. D. VANINADER CAST CUTTER Filed Sept. 18, 1955 INVENTOR. BERT DALra/v VAN NADEI? I BY W ATTORNEY.

are, 1937 POl-FIC ,---s.1.sm' I Bert name vim Nadcr, Berkeley, our.

September 10,1935, Serial no. 41.:

a claims. (01. m-sm "the invention to improvements in plaster cast cutting instruments for surgical use in which an oscillating cutter operates in con junction with a stationary cutter -to which a shield, or foot, is suitably attached'which serves to protect the fiesh of the patient against injury 'brithe cutters.

The objects of the improvements are First, to provide a cast cutter with which a plaster cast may be cut open and removed from any part of a patients body with greater ease, safety and dispatch than has been possible hereakin I itively cut any and all materials which may be used, in the making oi surgeonsplester'casts.

toiore.

M t provide a cast cutter'that will We such asplaster of Paris, cotton. wool, stockinette,

q anmaterials.

, to provide a cast cutter for cutting a cast which fits closely around the hard and surf oi the body, such as the head, hands,

and feet.

F to provide a cast cutter that will cut from the outer side of the east through to the inner side nearest the body of the patient.

Fifth, to provide a cast cutter, in the operation of which, the force necessary to operate it will be applied in a direction away from the body of the patient instead oi toward it, as has been the common practice.

B, to provide a cast cutter that will eliminate the possibility of injury to the patient during the cutting of the cast and also eliminate the .fear of being injured from the patient's mind.

useful, are: v

First, the very thin, smoothiprotective shield,

Seventh, to provide a cutter which will automatically clean itself of debris during thecutting process.

Eighth, to provide a cast cutter that will make.

or foot, which is interposed between the cast and the patients body directly under the cutters and positively prevents any injury to the patient. The extreme thinness of the foot allows it to be inserted between'the cast and 'the firm bony parts of the body without the creation of pressure on the usuallytender fiesh thereby causing pain to the patient. This has not been possible j. with other typeso'fcutters in common use. The

provision of the foot also removes the fear of being cut or otherwise injured from the patient's mind. 1 a

Second, the enangementand method ,of cutting from the.

outer side of the cast through-to the body is first covered with padding materials before the plaster of Paris and bandages are ap-- plied. Therefore it is obvious that any cutter operating .from the inside, outwardly, must cut through all of the fibrous padding before the plaster cast is contacted, which causes great difficulty due to the fact that, unless the instrument is very sharp, it cannot properly shear the fibers and the loose fibers are very liable to clog the cutters. with the device of my invention the cut is started from the outside with no inter ference from the padding. large and substantially constructed movable cutter operating on the outside ofthe-cast where room is plentiful. In my d there are no cutting parts between the cast and the patint's body which will possibly injure'the tients flesh, and in cutting from the outer side. toward the innerside the protective footis pulled firmly the inner side of the cast, away from patients body, thereby creating no pressure on the body with. the attendant pain caused by such pressure.

Third, the self-cleaning feature of. the mov-' able cutter. After the cutting stroke is made and the movable cutter is oscillated in the 0pposite direction from the cutting stroke, the cutter is .draggedbackward through the slotcut in the castand due to the friction of the debris collected'in the cutting teeth, dragging against the sides of the slot cut in the cast, thedebris is automatically dislodged from the teeth thereby enabling the teeth to take a full out during the following cutting stroke.

Fourth, this design allows the provision of very the inner side for these reasons: In the practice of applying plaster casts, the injured part of This design allows a thin wide cutters,'requiring little eflort to op- 'erate, and creating very little-debris during the vcuttins operation.

Fifth, the design of the instrument insures that all of the-force used in cutting will be applied in a direction away from the patients body.

- The preferred form of the invention is illus-' trated in the accompanying drawing, in which, Fig. 1 is a perspective .yiew of. the entire instrument, viewed from the topand front. Fig. 2

is aside elevational view of the inverted instru- 'by'the patient is protected end of the plate opposite that carrying the foot is an arm 3 provided at its outer end with a handle l; and formed at the junction of the arm and plate is an aperture which receives a pivot bolt ii.

On the bolt 8 is journaled an arm E5, of a thickness slightly greater than that of the plate i. Said arm is provided with a handle 1 at its outer end and cutter teeth 5 formed in the portion thereof adjacent the pivot pin, each of the teeth being formed with a bevel i i which provides a cutting edge along one side of the tooth in addition to the cutting edge provided across the thickness of the tooth at the distal end thereof. It will be noted that each successive tooth is spaced radially from the axis of the pivot bolt a slightly greater amount than the next preceding tooth and that the tooth which is spaced farthest from the bolt axis will, when moved about the axis, by movement of the arm 6 to a position overlying and passing arm 3, just contact the upper surface of the foot 2, the remainder of the teeth meanwhile having passed successively past the beveled edge I! of the plate I.

To provide for maintaining the contacting surfaces of the arms in close engagement so that the cutting edges of the teeth and the plate i will readily shear material placed therebetween, I provide the pivot bolt with a nut 9 which is maintained in its adjusted position by means of a lock nut i0.

Describing the operation of the device, the foot 2 is placed between the cast to be cut and the surface of the patients body covered thereby so that the end of the cast will project into the gap provided between the upper surface of the foot and the adjacent edge of the arm 3, the arm 6, of course, having been first moved to the position illustrated in Figure 1. When the instrument has been so placed is moved toward the arm 3 which causes the cutter teeth to gouge into the plaster, or other material of which the cast is composed, and cut a slot therein which is gradualLv deepened as the successive teeth complete theircuts until, when the final tooth has passed through the slot and contacted the upper surface of the, foot 2, that portion of the length of the cast equivalent to the difference in radial spacing between the first and last teeth of the series, will be completely out through. Returning the arm 6 to its extended position shown in the figure will allow the instrument to be drawn lengthwise of the cast into the slot previously cut and allow a fresh portion of the latter to enter the gap between the foot and arm where it will be acted upon during the succeeding passage of the teeth toward the plate. It will be observed that the device is pulled instead of pushed against the cast during operation, .thus facilitating the control thereof whereagainst injury.

Most all casts have some sort of fibrous material embedded therein so as to reinforce the plaster and render it less liable to fracture.

on the cast, the arm 6 It cutting anot er I is to sever this fibrous material that the beveled cutting edges ii and I! are provided respectively on the teeth and plate. Although it is contemplated that at least one of the cutter teeth will contact the surface of the foot and thereby completely cut through the cast, itis possible that under some exceptional condition the teeth may not completely sever the full thickness of the cast, thereby leaving a thin uncut portion there-' of. This, however, will not aflect the emcient operation of the instrument for the reason that as pressure is appliedby the operator pulling the instrument lengthwise of the cast the thin uncut portion of the latter will be severed or displaced by the sharp advancing edge of the plate i.

It will be observed that the arm ii is set at an angle, preferably about 20, with respect to the foot 2, this construction being provided so that the line of thrust of the slight pull exerted on the instrument by the operator will be in a direction away from the patients body and thereiore not liable to create a painful pressure on the flesh; furthermore, it will be observed that when the device is operatively positioned on the cast the arm 3 rises outwardly at an angle from the surface thereof and consequently the arm 6 may be moved therepast toward the cast, thus permitting the last cutting tooth to not only contact the foot but move into shearing relationship with the cutting edge of the plate.

It will be also observed that, due to the eccentric positioning of the cutter teeth, the latter, when moving through the cast material, will create a thrustwhich will actually feed the cutting structure along the line of the cut, therebymaterially increasing the length of the cut during each stroke.

It will further teeth are very narrow only a small amount of debris is produced even though the out be of considerable length, and that, since the teeth are oscillated back and forth through the slot being cut, maximum cutting efllciency is obtained. In

be seen that since the cutter this connection it has been found in practice that on the advance-or cutting stroke some of the excavated material becomes lodged in the tooth notches. However, on the return stroke the debris so lodged between the teeth will, through frictional contact with the sides of the slot, be

dislodged and the cutting structure thereby con-- ditioned to excavate the maximum amount upon the next succeeding cutting stroke.

I claim:

1. A cutter for removing casts from bodies, comprising a relatively thin, flat member adapted to pass between a cast and a body, a plate rising from said member and provided-with a cutting edge, an arm movably mounted on said plate,

' said arm having teeth thereon provided with cut-. ting edges cooperative with the cutting edge of said plate to cut through a cast positioned above said member, and means extending from said plate for guiding said plate through the cut made in said cast by said teeth.

2. A cutter for removing casts from bodies, comprising a relatively thin, flat member adapted to pass between a cast and a body, a plate rising from said member and provided with a cutting edge, an arm movably mounted on said plate, said arm having teeth thereon provided with cutting edges cooperative with the cutting edge of said plate to cut through a cast positioned above said member, said teeth each having an additional cutting edge acting independently of the edge of said plate, and means extending carcass?v thereon provided with cutting edges cooperative.

with the cutting edge of said plate to cut through a cast positioned above saidmember, said teeth being successively disposed at increased radial distances from the axis of movement of said movable arm, and means extending from said plate for guiding said plate through the out made in said cast by said teeth. a

4. A cutter for removing casts from bodies, comprising a member adapted to pass between a cast and a body, a plate rising from said memher and provided with a'cutting edge, an arm movably mounted on said plate, said arm having teeth thereon provided with cutting edges cooperative with the cutting edge of said plate to cut through a cast positioned above said member, said teeth being successively disposed at increased radial distances from the axis of movement of said movable arm, and at least one of said teeth being engageable with said member, and means extending from said plate for guiding said plate through the cut made in said cast by said teeth.

5. A cutter for removing casts from bodies, comprising a member adapted to pass between a cast and a body, a plate rising from said memher and provided with a cutting edge, an arm movably mounted on said plate, said arm having teeth thereon provided with cutting edges cooperative with the cutting edge of said plate to cut through a cast positioned above said member,

4 edge extending upwardly .from a surface of said member, an arm extending from said plate andsaid teeth being successively disposed at increased radial distances from the axis of movement of said movable arms, and at least one of said teeth being engageable with a surface of said member when said; tooth is in cooperative relationship with the cutting edge of said plate, and a handle extending from said plate.

6. A cutter for removing casts from bodies,

comprising a member adapted to pass between a a relatively thin plate rising cast and a body,

from said member and providedwith a cutting disposed at an angle with the plane of said member, a movable arm pivotally mounted on said plate, a plurality of teeth formed on said movable arm having cutting edges cooperative with the cutting edge of said plate to cut through a cast positioned above said .member, said being positioned on said movable arm to pass, when said arm is moved, over the surface of said member at decreasing distances therefrom.

7. A cutter for removing casts from bodies, comprising a member adapted to pass between a cast and a body, a relatively thin plate rising from said member and provided with a cutting I edge extending upwardly from a surface-of said member, an arm extending from said plate and disposed at an angle with the plane of said member, a movable arm pivotally mounted on said plate, a plurality of teeth formed on said movable arm having cutting edges cooperativewith the cutting edge of said plate to cut through a cast positioned above said member, each of said teeth being positioned on said movable arm to,

pass, when said arm is moved, in a curved path over the surface of said member and along paths of constantly increasing'radil through said cast whereby said plate is drawn into displacing engagement with said cast.

8. A cutter for removing casts from bodies, comprising a thin fiat member adapted to pass between a cast and a body, a thin plate formed integrally with and rising from said member, said plate having a cutting edge thereon, a guiding arm extending from said plate and disposed-at an angle with the plane oi said member, a movable operating arm plvotally mounted on said plate adjacent said member, a plurality of teeth formed on an edge of said movable operating arm, said teeth each having a plurality of cutting edges,'one of said edges being cooperative with the cutting edge of said plate to cut through a cast positioned above said member, and another of said cutting "edges being adapted to excavate material from said ,cast, said teeth being positioned on said movable arm to pass, when said arm is moved, over the surface of said member at constantly decreasing distances therefrom, and the thickness of said teeth being greater than that of'said plate;

-9.;QA cutter forremoving casts from'bodies, omprising'a relatively thin, flat member adapted to pdssbetween a cast and a body, a relatively .thinplate rising. from said member and provided with'a cutting edge. an arm integrally formed with said plate and disposed at an angle with the plane of saidmember, and a movable arm pivotally mounted on said plate, said arm having a flattened end portion formed with cutting teeth inthe edge thereof adapted to cooperate with the positioned above said member.

cutting'edge or said plate to cut through a, cast 

